LIGO - Was It All Just Noise?

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chelle
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LIGO - Was It All Just Noise?

Post by chelle » Sat Jun 17, 2017 9:45 am

New article/paper on the LIGO gravity waves detector, asking the question if it was simply noise.

This begs for an other question if the LHC is actually able to detect anything out of the ordinary, such as collision-waves that might combust surrounding matter and cause a global inferno fueled by sub-atomic disruptions. How can we see the warning signs through all that noise and tell what's what, apparently we fail at this. :?

https://www.forbes.com/sites/startswith ... detections
Analysis of the data attributed the signal to a black hole merger that happened several billion light years away. But what if there wasn't a signal at all, but rather patterns and correlations in the noise that fooled us into believing we were seeing something that wasn't real? A group of Danish researchers just submitted a paper arguing that the celebration might have been premature.
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Re: LIGO - Was It All Just Noise?

Post by mfb » Sun Jun 18, 2017 1:07 am

The arxiv submission is very questionable. They don't even consider how LIGO evaluated the background.
Not surprising that LIGO doesn't bother writing much about it.
A major shortcoming of the Danish group’s analysis that they pointed out to me is that the Danes use methods based on tutorials from the LIGO Website, but these methods do not reach the quality standard of the – more intricate – data analysis that was used to obtain the published results.
More discussion here.

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Re: LIGO - Was It All Just Noise?

Post by chelle » Sun Jun 18, 2017 8:54 am

mfb wrote:The arxiv submission is very questionable.
A major shortcoming of the Danish group’s analysis that they pointed out to me is that the Danes use methods based on tutorials from the LIGO Website, but these methods do not reach the quality standard of the – more intricate – data analysis that was used to obtain the published results.
Not having published the 'more intricate' analysis makes the original LIGO publication 'verry questionable' to start with. :mrgreen:

Edit: What the heck is the 'more intricate – data analysis' ??
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Re: LIGO - Was It All Just Noise?

Post by mfb » Sun Jun 18, 2017 1:04 pm

chelle wrote:
mfb wrote:The arxiv submission is very questionable.
A major shortcoming of the Danish group’s analysis that they pointed out to me is that the Danes use methods based on tutorials from the LIGO Website, but these methods do not reach the quality standard of the – more intricate – data analysis that was used to obtain the published results.
Not having published the 'more intricate' analysis makes the original LIGO publication 'verry questionable' to start with. :mrgreen:
LIGO published the 'more intricate' analysis. That's what Sabine is saying. They published the results and how they got it. The group here ignored that and used a very questionable analysis method.

What it is: The way LIGO estimated the background. Taking data from two weeks (not just 20s as the group here did) and looking for random correlations.

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Re: LIGO - Was It All Just Noise?

Post by chelle » Sun Jun 18, 2017 5:27 pm

mfb wrote:LIGO published the 'more intricate' analysis. That's what Sabine is saying.
I am not sure about this. :think:

The Danish group used the method published by LIGO on their webside, and it was 'a mojor shortcoming' vs. the 'more intricate' method. The article doesn't state if LIGO actually also published that 'more intricate' method somewhere. As she wrote:
A major shortcoming of the Danish group’s analysis that they pointed out to me is that the Danes use methods based on tutorials from the LIGO Website, but these methods do not reach the quality standard of the – more intricate – data analysis that was used to obtain the published results.
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Re: LIGO - Was It All Just Noise?

Post by mfb » Sun Jun 18, 2017 11:10 pm

chelle wrote:The Danish group used the method published by LIGO on their webside
"Made public" - what they put on their website was not the publication. It was "here, if you want to play around a bit with the data, why don't you do that".
The article doesn't state if LIGO actually also published that 'more intricate' method somewhere.
Not explicitly, but I think it is clearly implied. And I know the original publication. Yes they did.

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Re: LIGO - Was It All Just Noise?

Post by chelle » Mon Jun 19, 2017 8:55 am

mfb wrote:
chelle wrote:The article doesn't state if LIGO actually also published that 'more intricate' method somewhere.
I know the original publication. Yes they did.
They have discussed the 'more intricate method' in their paper, but they didn't publish the method itself.

Anyway, I guess that's not the key issue here, the claim is that the 'more intricate method' found 'patterns and correlations in the noise' and claimed it are Gravity Waves while it can be just noise.

This also brings me back to my first remark:

"… if the LHC is actually able to detect anything out of the ordinary, such as collision-waves that might combust surrounding matter and cause a global inferno fueled by sub-atomic disruptions. How can we see the warning signs through all that noise and tell what's what, apparently we fail at this." :?
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Re: LIGO - Was It All Just Noise?

Post by chelle » Mon Jun 19, 2017 9:37 am

chelle wrote:Apparently they have published everything, here's a reaction from LIGO:
http://www.preposterousuniverse.com/blo ... uest-post/
But it seems to be besides the point as the issue is with the templates, as explained in the video by the Danish professor: http://www.physik.uni-muenchen.de/aus_d ... index.html

It also puts my argument, of how to detect collision vibrations at the LHC, back on the table. :mrgreen:
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Re: LIGO - Was It All Just Noise?

Post by mfb » Wed Jun 21, 2017 10:32 am

Thanks for sharing the recent blog link.
chelle wrote:It also puts my argument, of how to detect collision vibrations at the LHC, back on the table. :mrgreen:
There is not even an argument. Randomly collecting words is not an argument.

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Re: LIGO - Was It All Just Noise?

Post by chelle » Wed Jun 21, 2017 12:23 pm

mfb wrote:
chelle wrote:It also puts my argument, of how to detect collision vibrations at the LHC, back on the table. :mrgreen:
There is not even an argument. Randomly collecting words is not an argument.
That wasn't an argument on itself, it was a reference to the argument in my first post:
This begs for an other question if the LHC is actually able to detect anything out of the ordinary, such as collision-waves that might combust surrounding matter and cause a global inferno fueled by sub-atomic disruptions. How can we see the warning signs through all that noise and tell what's what, apparently we fail at this. :?
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Re: LIGO - Was It All Just Noise?

Post by mfb » Wed Jun 21, 2017 2:01 pm

Yes, I was referring to that post.
It is a random collection of words without any physics in it.

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Re: LIGO - Was It All Just Noise?

Post by chelle » Wed Jun 21, 2017 4:24 pm

mfb wrote:Yes, I was referring to that post.
It is a random collection of words without any physics in it.
The physics is straightforward, when you collide particles do you produce waves that travell through the Higgs Field (SpaceTime) that shake up surrounding matter, like when you drop a stone in a pond, and how you get waves rippling. So not the the Quarks and Gluons that emerge out of the collisions and who form linear pathways that decay tree-wise into smaller paths and jets, but more like the spherical sound waves that travel through the air after a blast … and that can blow your eardrums.
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Re: LIGO - Was It All Just Noise?

Post by mfb » Wed Jun 21, 2017 6:50 pm

when you collide particles do you produce waves that travell through the Higgs Field
No you do not.
Do you really want to drive your own thread off-topic?

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Re: LIGO - Was It All Just Noise?

Post by chelle » Wed Jun 21, 2017 7:03 pm

mfb wrote:
when you collide particles do you produce waves that travell through the Higgs Field
No you do not.
Do you really want to drive your own thread off-topic?
It's not off-topic, because the issues with the LIGO experiment show how difficult it is to detect something within the noise. As a matter of fact it was pointed out in the presentation by the Danish professor that LIGO can only look within a certain region, and thus it has only a limited kind of events that it can spot, because of all the other noise that needs to be filtered out. So the question can be raised what are the LHC detectors missing due to the noise covering up large parts of what's going on. So we don't know, or better we can't know all we can do is cross our fingers.
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Re: LIGO - Was It All Just Noise?

Post by mfb » Thu Jun 22, 2017 10:13 am

The background of gravitational wave detectors and the background in particle physics experiments are completely different things.
So we don't know, or better we can't know all we can do is cross our fingers.
Maybe you don't know. Particle physicists do know it.

Some things are very easy to spot (e. g. Z bosons and J/Psi), some are harder to spot (e. g. the Higgs), and some things are so rare and hard to spot that they haven't been found yet (e. g. Higgs -> Z gamma decays). In general, larger datasets mean more things can be found. This is a bit different from gravitational wave detectors, where you are interested in individual events. You cannot repeat anything, every event is unique.

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